Process for dyeing leather



2,257,694 UNITED STATES PATENT OFFICE raocrzss m ammo mama Adolf Kreboer, Biehen, near Basel,- Swltaerland, mlgnor to J. B. Geigy A. (1., Basel, Switzerland No Drawing. Application April 2, 1940, Serial "Patented Se t 30, 1941 .at least 3. dyestuffs constructed according to the above No. 327,520. In Switzerland April 27, 1939 12 Claims.

It has been found that leather can be dyed full and deep shades, by using diazo dyestuffs of the general formula Al*I=N-BN=N Nan I wherein A means the radical of a dlphenylamine sulphonic acid, B means a naphthalene radical. containing the two azo groups irip-position, and R means an alkyl' or aryl group of the benzene series, the number of sulphonic acid groups contained in the dyestuif molecule being For the manufacture of the disazo deep blue to black colors having an excellent fastness to polishing.

Disazo dyestuffs of a similar structure with a-naphthylamine as middle-component and naphthols or naphthol sulphonic acids as endcomponents have already been used for dyeing wool (see Schultz, Farbstofitabellen, 7th edition, lst tome, No. 590), as well as similar products with amines of the benzene or naphthalene series as initial components, a-naphthylamine or Cleve acids as middle-components and l-alkylor 1- arylaminonaphthalene-8-su1ph0nic acids as endcomponents (Schultz, l. c. No. 552 and 594). But the dyeings thereof do not show the full and deep blue or blaclr shades or chrome-velourleather and do not possess the good fastness to flolishing as the dyestuffs of the present inven- Exnmma r03 rm: Drama Paocuss The chrome-tannedskins'having been polished and softened as usual, are introduced with 300% of water of 60 C. into the dyeing drum and 10% of 'thedyestufi 4'-nitro-4-aminodiphenylamine-2-sulphonic acid-azolaminonaphthalene-G- and 7-sulphonic acid-mixture-azo-flphenylaminonaphthalene-B-sulphonic acid, hot

dissolved in the twentyfold quantity of water,

are added through the hollow axis of the drum. After minutes 5% of formic acid of 80% strength are added, then the drum. is allowed to still move for an hour and the whole is worked as usual. It results a flowery full black of good fastness to polishing.

EXAMPLE ron THE lliawvrncruaa or THE Dras'rurrs 30.8 parts of 4'-nitro -aminodiphenylamine- 2'- sulphonic acid are diazotized according to' the known method and coupled with 22.3 parts of the technical mixture of l-aminonaphthalene-S- and -'7-sulphonic acid. The obtained monoazo 3o dyestufi is dissolved in water with 4 parts of caustic soda lye of strength, then 7 parts of sodium nitrite are added and the mixture is caused to flow at 0 C. under cooling into 35 parts of hydrochloric acid of 30% strength. The diazotatlon being finished, the diazonium compound is combined in the cold and in the presence of sodium acetate with 21.9 parts of l-phenylaminonaphthalene-B-sulphonic acid. The coupling is completed within a short time. The formed dyestufl is precipitated with .common salt, filtered and dried. It constitutes a black powder which dissolves in water with violet-black and in concentrated sulphuric acid with green-blue coloration.

The following table gives a series of dyestuifs, which are used according to the present process,

and the shades obtained with these dyestuffs.

Table lst component 2d component 3d component fi gg gf in di hen lamlne-T-sul- Mixture oi l-aminonaphthalene-o-' l-phen lamiuo-naplithalene-Ei-sul- Flowery black. 1 4 3152311.? p y and -7-sulphonic acid. phonic acid. z 2'-nitro+amlnodiphenylamihe-4'-sul- ..do 0 Full reddish-black.

phonic acid. 3 ethyl-4-amlnodIphenylamine-2- ..do o Flowerybiue-black.

sul honicac 4 4.am inodl henylamine-2-sulphonic ..do 0 Deep blue.

acid. 5 u .4-mmodl hen lamlne-z':3- a-naphthylamine o- Full black. a l' i i t gfig fnfiikhenylamine-Tsull-amlnonaphthalene-o-sulphonic l-p-tol l-aminonaphthalene-S-sul- Flowery black.

phonic acid. acid. phon 0 acid.

What I claim is: 1. A method of imparting full and deep blue to black shades to leather, which comprises dyeing the leather with a disazo dyestufi of the genwherein A means the radical of a diphenylamine sulphonic acid, B means a naphthalene radical containing the two azo groups in p-position, and

to black shades to leather, which comprises dyeing the leather with the disazo dyestufi 4-:nitro- 4-aminodiphenylamine-2'-sulphonic acidazol-aminonaphthalene-fi-sulphonic acid-azo 1-ptolyl aminonaphthalene-8-sulphonic acid.

4. A method of imparting full and deep blue to black shades to leather, which comprises dyeing the leather with the disazo dyestuff 4'-nitro- 4-aminodiphenylamine-2'-sulphonic acidazo mixture of l-aminonaphthalene-fiand- -7-sulphonic acidazo 1-phenylaminonaphthalene-8- sulphonic acid.

5. The disazo dyestuffs for dyeing leather having the following general formula AN=NB/N=N -NHR SO3H wherein A means the radical of a diphenylamine sulphonic acid, B means a naphthalene radical containing the two azo groups in p-position, and R means one member of the group consisting of alkyland aryl-groups of the benzene series, the

number of sulphonic'acid groups contained in the dyestuifs molecule being at least 3, said dyestuffs giving on velour-leather full and deep blue to black shades of good fastness to polishing.

6; The disazo dyestufl 4-aminodiphenylamine- 2-sulphonic acidazomixture of l-aminonaph-- thalene-6- and -7-sulphonic acidazo-+1-phenylaminonaphthalene-8-sulphonic acid, giving a full blue on velour-leather.

7. The disazo dyestufi 4'-nitro-4-aminodiphenylamine-2-sulphonic acid--azo l-aminonaphthalene-B-sulphonic acidazo 1-p-tolylaminonaphthalene-B-sulphonic acid, giving a flowery black on velour-leather.

8. The disazo dyestufi 4'.-nitro-4-aminodiphenylamine-2'-sulphonic acidazo mixture of 1- aminonaphthalene-6- and -7-sulphonic acidazo 1 phenylaminonaphthalene 8 sulphonic acid, giving a flowery black on velour-leather.

9. A process for the. manufacture of disazo dyestuffs for dyeing leather, comprising the steps of diazotizing anaminodiphenylamine-sulphonic acid, coupling the obtained diazo compound with anamine of the naphthalene series coupling in p-position, diazotizing the resulting monoazo dyestufi and coupling the obatined diazonium compound with a l-aminonaphthalene-B-sulphonic acid substituted in the amino group by a radical selected from the group consisting of alkyl and aryl radicals of the benzene series.

10. A process for the manufacture of disazo dyestuffs for dyeing leather, comprising the steps diazotizing l -amino-diphenylamine-2-sulof phonic acid and coupling with a mixture of l-aminona'phthalene-G- and -7-sulphonic acid, then diazotizing the resulting monoazo dyestuff and coupling the diazonium compound with l phenylaminonaphthalene 8 -sulphonic acid, thus realizing adyestufi' giving on velour-leather a flowery black shade.

11. A process for themanufacture of disazo dyestuffs for dyeing leather, comprising the steps of diazotizing' 4'-nitro-4-aminodiphenylamine- 2'-sulphonic acid and coupling with l-aminonaphthalene-6-sulphonic .acid, then diazoti'zing the resulting monoazo dyestuff and coupling the diazonium compound with L-p-tolylaminonaphthal'ene-S-sulphonic acid, thus realizing a dyestufi yielding a flowery black shade on velourleather. I p

'12. A process for the manufacture of disa'zo dyestufi's for dyeing leather, comprising the steps 'of'diazotizing 4' -nitro-4-aminodiphenylamine-2'- sulphonic acid and coupling with a mixture of l-aminonaphthalene-6- and -7-sulphonic acid, then diazotizing the resulting monoazo dyestufi and coupling the diazonium compound with lphenylaminonaphthalene 8 sulphonic acid, thus realizing a dyestuiI giving a flowery black on velour-leather.

ADOLF KREBSER. 

